This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Large bore reinforced hose can be utilized in a wide array of applications. One important application for large bore reinforced hose that is of growing importance in the world today is in loading and unloading oil tankers and floating production storage and offloading units (FPSOs). Such hose has an inside diameter of 5 cm or greater and typically has an inside diameter ranging from 20 cm to 80 cm. Such hose for offshore applications is also typically designed to include a floatation medium to provide the hose with sufficient buoyancy so that it will float on the surface of water. Hose for offshore applications typically has reserve buoyancy when filled with sea water which is within the range of 10% to 40%. A reserve buoyancy of at least 20% is frequently demanded by customers. Because vast reserves of petroleum are located under water in many locations around the world including under the North Sea, the Gulf of Mexico, off the coast of Brazil, and off the coast of California there is a growing demand for large bore reinforced floating hose.
Transferring the crude oil from FPSOs to shuttle tankers at sea is an extremely demanding task because of the persisting relative movement between the vessels. During times of adverse weather conditions, such as high waves, high winds, and storms at sea, this task becomes even more difficult. Floating hoses typically run from the bow and/or the stern of FPSOs to shuttle tankers. Modern shuttle tankers may have a bow manifold for charging crude oil, but many conventional shuttle tankers have a charging device consisting of a midship manifold for intake of the oil load. For this reason a relatively long loading hose is needed, from the FPSO-vessel to the midship manifold on the shuttle tanker. The separation between the vessels, between the stern of the FPSO and the bow of the shuttle tanker is generally about 50 to 200 meters, and the extension of the floating hose is normally between about 150 and 300 meters.
When the floating hoses are not being used to transfer petroleum they can be allowed to remain floating on the water after being released from the tankers. However, in such cases where the floating hose is left on the water the floating hose may be damaged by being struck by ships, sea creatures or by the movement from waves in stormy weather. In any case, hose wear occurs due to continual wave action. This can lead to a loss of the buoyancy and/or primary carcass failure and over time the hose can begin sink.
In the alternative, the floating hose can be hoisted onto the FPSO for storage until it is again needed for offloading crude oil to a shuttle tanker. This can be done by using a wench to pull the floating hose onto a reel. This protects the hose from exposure to waves and the inherent wear associated therewith. It also eliminates the danger of the floating hose being struck by a ship as it is floating at sea. However, pulling the hose onto a reel puts the tapered fittings that connect different sections of hose under a tremendous amount of stress. At the point where the coupling is being pulled onto the reel it experiences a particularly high level of stress and compressive forces. Over time, these forces can cause the hose to fail at or near the point where it is attached to a coupling. In any case, large bore reinforced hoses are prone to failure at their tapered fittings. This is also the case where large tensile loads are encountered in catenary and deep water submarine applications.
Today, there is a need for tapered fittings for large bore reinforced hoses that are more resilient and which are capable of being incorporated into hoses that are more durable and capable of being repeatedly pulled onto reels and more resilient to high tension and bending loads. It would accordingly be desirable to develop tapered fittings for large bore reinforced hoses that are more resistant to failure and which have a longer service under harsh service conditions, such as being repeatedly pulled onto reels.